import math

str = input().split(' ')
x1 = float(str[0])
x2 = float(str[1])
y1 = float(str[2])
y2 = float(str[3])

result = (x1-y1)*(x1-y1) + (x2-y2)*(x2-y2)
result = math.sqrt(result) if result != 0 else 0

print('%.6f'%result) import math math str = input().split(' ') str input().split(' ') ().split () input split ' ' x1 = float(str[0]) x1 float(str[0]) float str[0] str 0 x2 = float(str[1]) x2 float(str[1]) float str[1] str 1 y1 = float(str[2]) y1 float(str[2]) float str[2] str 2 y2 = float(str[3]) y2 float(str[3]) float str[3] str 3 result = (x1-y1)*(x1-y1) + (x2-y2)*(x2-y2) result (x1-y1)*(x1-y1) + (x2-y2)*(x2-y2) (x1-y1)*(x1-y1) x1-y1 x1 y1 x1-y1 x1 y1 (x2-y2)*(x2-y2) x2-y2 x2 y2 x2-y2 x2 y2 result = math.sqrt(result) if result != 0 else 0 result math.sqrt(result) if result != 0 else 0 result != 0 result 0 math.sqrt(result) math.sqrt math sqrt result 0 print('%.6f'%result) print '%.6f'%result '%.6f' result x1 = float(str[0]) float(str[0]) x1 result = (x1-y1)*(x1-y1) + (x2-y2)*(x2-y2) (x1-y1)*(x1-y1) + (x2-y2)*(x2-y2) result x2 = float(str[1]) float(str[1]) x2 y1 = float(str[2]) float(str[2]) y1 result = math.sqrt(result) if result != 0 else 0 math.sqrt(result) if result != 0 else 0 result y2 = float(str[3]) float(str[3]) y2 str = input().split(' ') input().split(' ') str
import math

str = input().split(' ')
x1 = float(str[0])
x2 = float(str[1])
y1 = float(str[2])
y2 = float(str[3])

result = (x1-y1)*(x1-y1) + (x2-y2)*(x2-y2)
result = math.sqrt(result) if result != 0 else 0

print('%.6f'%result)